Vision is the most important function of the eye, and many diseases of the eye can cause vision loss. If rapid vision loss occurs in a short period of time, it is usually due to the following reasons: First, due to optic neuritis, which can be diagnosed within 2-3 days when vision decreases to the point where only the movement of the hand can be distinguished, or even the brightness or darkness of the ambient light, and a visual electrophysiological examination can show obvious waveform abnormalities, and the disease Second, due to ischemic optic neuropathy, most of the disease is caused by embolism of the nutrient vessels of the optic nerve, such as the short posterior ciliary artery or acute ischemia of the optic nerve, which can cause vision loss. Fourth, myopia occurs due to excessive eye use, and vision loss follows.